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From: Jens Axboe <[email protected]>
To: Hao Xu <[email protected]>, [email protected]
Cc: [email protected]
Subject: Re: [PATCH 3/6] io_uring: allow allocated fixed files for openat/openat2
Date: Thu, 12 May 2022 06:23:21 -0600	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 5/12/22 2:21 AM, Hao Xu wrote:
> ? 2022/5/9 ??11:50, Jens Axboe ??:
>> If the application passes in IORING_FILE_INDEX_ALLOC as the file_slot,
>> then that's a hint to allocate a fixed file descriptor rather than have
>> one be passed in directly.
>>
>> This can be useful for having io_uring manage the direct descriptor space.
>>
>> Normal open direct requests will complete with 0 for success, and < 0
>> in case of error. If io_uring is asked to allocated the direct descriptor,
>> then the direct descriptor is returned in case of success.
>>
>> Signed-off-by: Jens Axboe <[email protected]>
>> ---
>>   fs/io_uring.c                 | 32 +++++++++++++++++++++++++++++---
>>   include/uapi/linux/io_uring.h |  9 +++++++++
>>   2 files changed, 38 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>> index 8c40411a7e78..ef999d0e09de 100644
>> --- a/fs/io_uring.c
>> +++ b/fs/io_uring.c
>> @@ -4697,7 +4697,7 @@ static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
>>       return __io_openat_prep(req, sqe);
>>   }
>>   -static int __maybe_unused io_file_bitmap_get(struct io_ring_ctx *ctx)
>> +static int io_file_bitmap_get(struct io_ring_ctx *ctx)
>>   {
>>       struct io_file_table *table = &ctx->file_table;
>>       unsigned long nr = ctx->nr_user_files;
>> @@ -4722,6 +4722,32 @@ static int __maybe_unused io_file_bitmap_get(struct io_ring_ctx *ctx)
>>       return -ENFILE;
>>   }
>>   +static int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags,
>> +                   struct file *file, unsigned int file_slot)
>> +{
>> +    int alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC;
>> +    struct io_ring_ctx *ctx = req->ctx;
>> +    int ret;
>> +
>> +    if (alloc_slot) {
>> +        io_ring_submit_lock(ctx, issue_flags);
>> +        file_slot = io_file_bitmap_get(ctx);
>> +        if (unlikely(file_slot < 0)) {
>> +            io_ring_submit_unlock(ctx, issue_flags);
>> +            return file_slot;
>> +        }
>> +    }
> 
> if (alloc_slot) {
>  ...
> } else {
>         file_slot -= 1;
> }
> 
> Otherwise there is off-by-one error.
> 
> Others looks good,
> 
> Reviewed-by: Hao Xu <[email protected]>

Thanks, you are correct, I've folded that in.

-- 
Jens Axboe


  reply	other threads:[~2022-05-12 12:23 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-09 15:50 [PATCHSET v2 0/6] Allow allocated direct descriptors Jens Axboe
2022-05-09 15:50 ` [PATCH 1/6] io_uring: track fixed files with a bitmap Jens Axboe
2022-05-09 15:50 ` [PATCH 2/6] io_uring: add basic fixed file allocator Jens Axboe
2022-05-09 15:50 ` [PATCH 3/6] io_uring: allow allocated fixed files for openat/openat2 Jens Axboe
2022-05-12  8:21   ` Hao Xu
2022-05-12 12:23     ` Jens Axboe [this message]
2022-05-13  5:28       ` Hao Xu
2022-05-13 12:25         ` Jens Axboe
2022-05-13 12:56           ` Jens Axboe
2022-05-13  4:38   ` Hao Xu
2022-05-13 12:28     ` Jens Axboe
2022-05-09 15:50 ` [PATCH 4/6] io_uring: allow allocated fixed files for accept Jens Axboe
2022-05-09 15:50 ` [PATCH 5/6] io_uring: bump max direct descriptor count to 1M Jens Axboe
2022-05-09 15:50 ` [PATCH 6/6] io_uring: add flag for allocating a fully sparse direct descriptor space Jens Axboe
2022-05-10  4:44   ` Hao Xu
2022-05-10 12:27     ` Jens Axboe
2022-05-13 10:56 ` [PATCHSET v2 0/6] Allow allocated direct descriptors Hao Xu
2022-06-09  8:57 ` Stefan Metzmacher
2022-06-10 11:06   ` Hao Xu
2022-06-10 11:28     ` Stefan Metzmacher
2022-06-10 13:04       ` Hao Xu

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